Method of grinding and smoothing glass.



W. L. KANN.

METHOD OF GRINDING AND SMOOTHING GLASS.

APPLICATION FILED 00T.26,1912. I 1975 1. U7. Patented Oct. 7

1913. 2 sums-sum 1.

W. L.'K'ANN.

METHOD OF GRINDING AND SMOOTHING GLASS.

APPLICATION FILED 0013.26, 1912.

Patented Oct. 7, 1913.

2 SHEETS-SHBET 2.

nnrrnn sari/a rs WILLIAM L. KANE, PITTSBURGH, PENNSYLVANIA.

- METHOD OF GRINDING AND SMOOTHING GLASS.

L@75',1@7 Specification of Letters Batent. Patented Get "Z 191$ Application filed October 26; 1912. Serial No. 727,978.

To all whom it may concern: sand deposited in the pits for the coarse Be it known that I, WILLIAM L, KANN, a sand, and when the flow of the water is swift citizen of the United States, and resident of the reverse action takes'place; that is, there Pittsburgh, Allegheny county, State of is considerable of the rough sand carried 69 Pennsylvania, have invented certain newand over into the pits intended for the finer useful Improvements in Methods of Grlnd- 'sand. The first action is not very harmful,

' ing and Smoothing Glass, of which the folbut it decreases the efiiciency of the coarser lowing is a specification. grades. The second action, however, is very This invention relates to a method and harmful as the mixing of the coarse-grades machines for grinding and smoothing plate with the finer grades scratches the glass and glass and has particular reference to the retards the finishing making it necessary to method and: means for handling the sand do the operation over again,in part or whole,

or abrading material and grading the same. =jas only glass which is uniformly properly Heretofore the practice has been to apply smoothed will make a desired fine polish on 7 the sand used in such machine in as coarse plate or other glass.

a condition as was possible to obtain it and g In the present application the method of then use six to eight finer grades until the utilizing the coarse sand and the used sand application of the final grade leaves the glass differ from the usual practice and consists almost polished. Asamatterofnecessity and broadly in feeding a suiiicient amount of economy the sand used and crushed and new sand to a hopper or other suitable reground down in the process of rough grindceptacle convenient to the grinding table ing is later used again for the finer grind- :and cutting off the supply of new sand. The ing. Generally the grinding machine has batch of new sand in the hopper is then a ditch arranged about its circumference into ;used in the same and only one machine for 30 which the sand and water which have been both the grinding and smoothing operations, used in the machine are thrown from the ,no new sand being mixed with the old and grinding tables by centrifugal'force. The such a continuous operation a predeterheavy sand deposits immediately in this cirlmined or fixed result is assured each time.

cular ditch and is returned to the table as By the arrangement of this'invention the long as there is enough coarse grit in it to sand 1s, 1n the process of grinding, ground do heavy grinding, while the finer grades finer and finer and graded-until the glass flow out of the ditch into a main ditch from Iis smoothed ready for polishing, when the which they are flowed into a series of collect- Sand iS too fine for further use and may be i it wh they e graded according to flowed off. The grading of the sand as it is their coarseness and the resultant material ground and reground in the machine is done is used in all machines for subsequent final separately for each batch of sand and each grinding. In such a system it is usual to machine, and the head of water and other connect the discharge from all machines into factors which usually vary in present procone set of grading pits. The fine a d r esses are kept constant, whereby much betradin its are divided by partitions d ter and more uniform results are obtained.

as the sand and water flows into the pits To properly carry out the invention and the grades which will be deposited by grav- Q attain the above and other objects, the arity into each pit is determined by the space rangement of apparatus as herein described betweenthe partitions and the height thereis pr id of. The number of machines varies greatly; In h rawings-Figure 1 illustrates a each, machine varies in its process from rough plan view of aninstallation for grinding, grinding to fine smoothing. Sometimes all smoothing and polishing glass, and comof the machines are running and sometimes prises two-independent machines; Fig. 52 is only part, so it can be readily seen that the a sectional view through the sand pits shoivin amount of sand and the amount of water ng th grinding, smoothing and polishing used with the sand is a constantly varyin machines in elevation. Fig. 3 is a detail, quantity, as a consequence of which the .foreshortened view of the tele copic pulsagrades of sand deposited in the different settor or elevating device.

tling pits will vary with the fluctuating flow In the illustration, 10 and 11 represent I of the water, the result being that when two rotatable grinding tables or platforms the flow is slowest there is considerable finer of the usual or any preferred construction,

shown) may be provided. sand from a supply or storage bin 18 is and of which there may be any number. The tables 10 and 11 support the glass plates and have the rotating pairs of rub in frames 141and 15 arranged to extend over the grinding tables 10 and 11. A. ditch or gut-ter 17 is provided beneath each of the tables 10 and 11 and extends beyond the circumference of the tables a short distance to catch the sand as it is thrown from the tables by centrifugal force. Suitable operating mechanism for these parts (not New unused arranged to be discharged through a screen 20 of suitable mesh into a new sand pit 19 which also holds a supply of water. The pumping mechanism which extends into the pit or receptacle 19 comprises a stationary tubular portion 21 siipported at the top of the well and having the discharge branches 22. As shown in Fig. 3, telescopically connected to the tube 21 there is a lower movable pipe 23 which may be raised and lowered into section 21 so as to adjust its position with reference to the bottom of the pit 19. Extending dot 11 through the 'section 21 and connectedj to spiders 230 and 231 rigidly mounted at opposite ends of the movable member 23 and extending almost to the lower end of the section 23 there is a compressed air pipe 24 which at its upper end is flexibly connected to a compressed air supply 25. In operation the compressed air is discharged into the lower portion of the elevator tube and by creating an upward current therein, will cause the sand and water to rise and discharge through the outlet pipe 22. The pipe 23 is raised and'lowered by moving the pipe 24 by means of a counterbalance weight 26 which is connected .to the upper end of the compressed air pipe 24. The latter and the lower section 23 of the telescopicwater and sand elevator are maintained at any desired adjustment. The elevating device is separated from the inlet thereto by a vertical partition 27 which divides the it 19 into two compartments. The partition is adjustable so that it can be moved into several positions as shown in dotted lines, whereby the sand may be graded and properly cleaned. before elevatmg. By introducing water under pressure into the pit 19, the new sand therein is first washed and cleaned of any muck, loam or foreign matter, the slimes and foreign matter flowing ofl'into ditch 44. This is accomplished by the 11 ward pressure and as a result the new sand is fully effective and clean. The lower end ofthe partition may be adjusted to any height above the bottom of the pit 19. The movable partition is very essential and makes the device practicable since it is then possible to control the speed of the rising current and by that means control and classify the sand contained in the stream according to its weight or specific gravity. This is due to the variation of the cross section of the pit compartment in which the elevator device is located. The clean sand delivered from the discharge pipe 22 is conveyed through pipes 28 to a new sand hopper 29 or 29 arranged in any convenient position above the tables 10 and 11 to deliver the sand to the latter. When sufficient new sand has been delivered to rind the glass level the new sand. suppy is turned ofi and the sand used in coarse, rinding is reused. Any excess of new san runs over into the receptacle 30 and is returned ,to the pit 19 by the pipe 31.. The sand discharging on to the tables 10 and 11 in its grinding action is thrown outwardly and with the water, discharges into the ditch 17 and l7 from which it is delivered through screens 32, 32 into separate pits 33 and 34, similar in construction to the pit 19. Each of the pits 33 and 34, and as many more as there are grinding machines, are provided with an arrangement for elevating sand therefrom, and movable partitions as is provided in the pit 19. v

The elevating device 35 located in the pit 33 has its discharge end connected to the pipe 36 which delivers sand raised from the pit 33 into'a hopper 37 located above the table 10. A hopper 37 above the table 11 receives sand from the pit 34 through the elevating mechanism 38 in the same manner. The hoppers 29 and 37 are arranged to discharge into a hopper 46 which delivers the sand or abrasive to the grinding, smoothing and polishing mechanism. The hopper 37 is connected by a trough 38 with a series of grading hoppers 39, 40, 41 and 42 the'last of which has a slime overflow connection 43 with the waste flue 44. The grading hoppers each have a valved connection with a pipe 47 which discharges into hopper 46 for delivery to the grinding devices. In'the successive grinding of the plate only the coarser materials are used over and over again and as a consequence, become adually finer and are perfectly graded 1n the grading hoppers 39 to 42 so that finally only the fine material without any coarser particles will be available for fine grinding. The slimes are therefore continually separated from the coarser particles in each cycle as the sand is circulated through the apparatus. The movable partitions 33? and 34 in the drainage pits 33 and 34 assist in grading the sand and by reason of the fact that a constant head of water is maintained in the grading hoppers and pit an effective 1 grading of the sand is uaranteed. All ex 4 cess of water in the we s 33 and 34 is conducted to the waste flume 44: by the overflow connections 45 and 45', thereby maintaining a constant head of water for grading purposes. To maintain the stream of water through the elevating devices ,35 and 38 uniform the air supply used in elevatin the water is kept at a constant pressure. imilar grading hoppers 39, 40, 41 and 42' are provided above the table 11 and a slime overflow connection 43 discharges into the waste 4.4.

By reason of the constant or fixed water and air ressure and telescopic elevating device used in this combination the grading of the abrasive can be absolutely controlled. When no more sand is required out of either pits 19, 33 or 34 in the operation and only wateris required to finish the grades in the various hoppers, the telescopic member of the elevating device may be lifted away from the sand contact in the pits while the operation is going .on, and without intermission.

Tn the arrangement shown each grinding and smoothing machine is a unit .complete in itself in which the whole process of rough grinding, fine grinding, smoothing and grading of the material is carried on. Each machine is independent of the action of its neighbors and by applying a constant head of water, the grading of the abrasive material both in the pump pits and in the fine sand supplying boxes can be predetermined -and regulated. The elevating device, movable partition, the fixed headof water and the fixed air pressure make it possible to ab- .solutely regulate the grading of the sand and thereby permits the use of the sand from coarse grinding down to smoothing, or until the sand has lost its further usefulness. What I claim is: 1. The method of grinding and smoothing plate glass which consists in placing the rough glass in a grinding apparatus, sup-' plying new coarse sand and water to said apparatus until-a sufficient quantity of such sand has been supplied to eiiect the rough grinding of the glass, circulating the used sand through an apparatus for separating the slimes and back to the grinding apparatus, whereby finer grinding may be effected, and repeating this operation with the same original batch of sand until the same is reduced to a fine grade and the glass is provided with a comparatively smooth surface.

2. The method of inding plate glass which consists in placlng the rough plates of glass in a grinding apparatus, feeding new coarse sand and water to said apparatus until a sufiicient quantity of such sand has been supplied to efiect the rough grinding, circulating the used sand away from and back to the grinding apparatus repeatedly, and in the course of each cycle separating out the slimes and the finer particles of sand, whereby the rough and smooth grinding-of the glass may be completed with a single and the same batch of sand.

3. The method of grading and smoothing glass which consists in lacing the rough glass in a suitable grin ing mecha nism, circulatin water and sand to and from the grinding mechanism repeatedly, separating out the slimes and grading the remaining sand while maintaining a constant head or pressure of water.

i. The method of grinding and smoothing glass which consists in placing the rough glass in a grinding machine, feeding new coarse sand and water to said machine, until a suflicient quantity of such sand has been supplied to effect the rough grinding, shutting ofi the supply of new sand, circulating water and'the used sand away from and back to the grinding machine repeatedly,

and in the course of each cycle separating out the slimes and grading the finer particles of sand While maintaining a fixed head or pressure of water to facilitate the grading ofthe sand whereby the .entire grinding operation may be completed in a single machine and with a single batch of sand.

In testimony whereof I afiix my signature in presence of two witnesses.

WILLIAM L. KANN. Witnesses:

H. C. Lr'rnn, K. R. MCCAFFREY. 

